1. Field of the Invention
The present invention is situated in the field of the packaging technology and concerns a method and a device for packaging of flat objects or of small groups of flat objects with the aid of a packaging material that is supplied as a quasi-endless web. The packaging material is in particular a weldable plastic film or sheet material supplied from a reel.
2. Description of Related Art
A known method for continuously packaging individual printing products or small batches of printing products using a web of a plastic film or sheet material supplied from a reel comprises guiding a product stream, in which the products to be packaged are oriented parallel to the conveying direction and are conveyed behind each other and spaced from each other, between two webs of the packaging material or joining the product stream with one web and then wrapping the web around the products or around the product stream respectively. Then the web or webs of film material are sealed parallel to the conveying direction, and they are sealed and separated in the gaps between the products, i.e. transverse to the conveying direction. Such a method and a device for carrying out the method are described, for example, in the publication EP-1188670.
Packaging methods as mentioned above reach their limits regarding performance in produced packages per time unit relatively soon, because the products are conveyed in parallel to the conveying direction and behind each other, which for a high performance, particularly in the case of products being relatively long in conveying direction, leads to conveying speeds that are not easily achieved.
Higher piece performances at easily achieved conveying speeds are known to be possible if the products are conveyed in a conveying stream in which they are not aligned in parallel to the conveying direction but essentially transverse to it. The publication EP-0588764 (Grapha Holding AG) describes a device that is apparently suitable for packaging products being conveyed in such a manner. The device comprises a processing drum of the kind used, e.g., for inserting supplements into printing products or into folded sheets of packaging material. The plastic web is drawn from a supply point at the drum periphery in a zig-zag motion into the compartments of the drum, which are arranged in succession around the circumference of the drum. The bags thus produced are then charged with products, separated, and sealed, and the completely packaged products are removed from the drum compartments.
In the publication DE-3838985 (MAN) an equivalent device for batch-wise operation is described in more detail. With the aid of this device a plastic film web supplied from a supply reel is spread out in a zig-zag, creating a predetermined number of V-shaped bags, which are open along three edges and in which the products to be packaged are positioned. Then the bags are separated, closed around the product, sealed along the three open edges, and discharged from the device. Not until then another given number of bags are formed and the procedure is repeated. For each bag to be fashioned in one batch an essentially identical part-installation is provided and all device-parts are operated simultaneously.
Particularly from the publication EP-3838985 it is evident how complicated the known devices for packaging flat objects with a packaging material supplied from a reel are, and how many movable and individually controlled parts they have to comprise.